Usefulness of low- and high-volume multiple rapid swallowing during high-resolution manometry.

Background: It has been suggested that multiple rapid swallowing should be added to oesophageal manometry.
Aim: To prospectively evaluate whether 10 and 200 mL multiple rapid swallowing provide different information concerning motor function.
Methods: 30 consecutive patients with oesophageal symptoms, 13 achalasia patients after successful pneumatic dilation and 19 healthy subjects performed eight 5 mL single swallows, two 10 mL and one 200 mL multiple rapid swallowing.
Results: Almost all of the healthy subjects and two-thirds of the patients with oesophageal symptoms showed motor inhibition during both 10 and 200 mL multiple rapid swallowing. The oesophago-gastric pressure gradient was significantly higher during 200 mL multiple rapid swallowing within each group (p < 0.01), and significantly higher in the achalasia patients than in the other two groups (p < 0.0001). Presence of a contraction and increased contraction strength in comparison with single swallows were both more frequent after 10 mL than after 200 mL multiple rapid swallowing in the healthy subjects and the patients (p<0.05).
Conclusion: Motor inhibition could be similarly evaluated by means of 10 and 200 mL multiple rapid swallowing; 10 mL evaluated the after-contraction, whereas 200 mL multiple rapid swallowing was more valuable in identifying increased resistance to outflow.
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